DE 1467023 discloses a process for producing so-called “dry water”, in which liquid droplets are surrounded by hydrophobicized, pyrogenically produced silicon dioxide particles. As a result of the shell made of silicon dioxide particles, the liquid droplets are prevented from coalescing, and a pulverulent mixture is formed. The water can be released again by rubbing.
EP 0855177 A2 discloses a lightening powder which comprises, inter alia, 0.1-7% by weight of hydrophobicized silica, 5-40% by weight of polyhydric alcohols and 50-94% by weight of water. A higher fraction of polyhydric alcohols is described as being disadvantageous for the skin feel. For a mixture with a water content of less than 50%, incomplete liquidification is predicted.
Encapsulation of a liquid phase by hydrophobicized silicic acid particles, where the liquid phase comprises water as main constituent, has also been disclosed. However, only substances which are soluble in the water phase or are miscible with the water phase can be added to these formulations. Moreover, “dry water” formulations react sensitively to the addition of additives, meaning that in some circumstances no core-shell structure is formed. It follows from this that “dry water” formulations are subject to limitations both with regard to the additives that can be used and also their concentration.
Moreover, “dry water” formulations often have limited stability. In the event of prolonged storage, especially at elevated temperatures, the water enclosed in the shell evaporates. As a result, the composition of the product changes over time. In the case of closed storage of a “dry water”, the evaporated water condenses during cooling on the container wall and collects at the bottom of the container, meaning that the “dry water” formulation can no longer be used.